Tread for surfaced roads and pavements



July 9, 19 29. J BARRETT 1.720.461

TREAD FOR SURFACED ROADS AND PAVEMENTS Filed Dec. 24, 1926' Mam iii

Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

TREAD FOR SURFACED ROADS AND PAVEMENTS.

Application filed December 24, 1926.

This invention relates to improvements in the construction of roads and runways for vehicles and pavements for pedestrian traffic. The invention has application to any type of road, and to trackways, platforms, bridges and pavements.

The principal object of the invention is to provide a novel form of tread for wheels of the vehicles so constructed and built into the road or trackway that a practically 11ondestructive tread is provided adapted to relieve the more destructible portions of the roadbed from the weight and destructive effects of the greater part of the traliic.

Another object of the invention is to provide a novel form of tread element adapted for use in connection with bituminous roadways and so form-ed that when properly built into the roadway it is cushioned by the bitiu ruinous materials which form the major portion of the road surface.

Another object of the invention is to pro vide a. novel form of tread plate adapted for insertion in concrete of bituminous roadways to form a tread for the vehicle wheels and constructed as to securely interlock with the material of the roadway or trackway to prevent displacement of the tread elements and to reinforce the roadbed.

Another object of the invention is to provide a novel form of tread plate so formed to obtain a cushioning etl'ect .lilODl a body of bituminous material below the plate and to prevent extrusion or pressing out of the material from under the plate with a consequent formation of irregularities in the road surface.

The invention further conten'iplates the provision of tread-forming and reinforcing elements for use in connection with bituminous road or track surfacings with cooperatin elements adapting it for use on surfaced bridges, wooden. runways, platforms and the like whereby the bitumen is retained in proper position under and around the treml-forn'iinp elements.

The foregoing and other useful ends are obtainable by the devices illustrated in the at Serial No. 156,953.

Fig. 2 is a view of an alternative form of sheet metal tread plate; and

Fig. 3 is a fragmentary perspective view illustrating the tread plates as applied to bridges, wooden runways and the like, and

Fig. -1- a section on the line el l, Fig. 3.

Referring, to the drawings, the plate 13 shown'in Fig. 1 is provided at its edge with depending flanges 14 which are provided with spaced recc. 15. The upper surface of the plate is provided with vertical flan ges 16, the upper edges of which form the tread surface as hereinafter set forth. These flanges 16 are formed by striking them out of the body of the plate, thereby leaving for each flange an opening 17 in the top of the plate. This plate may be made of a width corre sponding to the e'llbctive widtl'i of the treul and a sufficient number of the plates are laid end to end to give a tread of the desired length.

In applying this tread plate to the roadhed,

the plates are laidu] )on the foinulatirm. and a bituminous or concrete mixture poured over and around them. to a depth cor rsponding to the overall height of the plate lroin the bottoms of the flanges 14 to the upper edges of the flanges 16. A bituminous or concrete mixture employed ot sullicient lluidiity to enable it to flow through the ojuen'iiug's l7 and 15 so as to entirely fill the space beneath the plates and create a solid and completely bonded roadway. The flanges 14; are of particular value in connection with bituminous and like surfacing materials, in that when the bituminous nuiterial has cooled or hardened, there is no tendency for the weight of traliio to cause itto spread or flow outwardly from under the plates. The bituminous inixtu re beneath the plate has a cushioninc; effect giving a resiliency to the road sur face which would not otherwise be present andat the same time the upper edges of the flanges 16 form a wearing; surface which is saibstantially permanent and capable of with standing allof the stresses and strains to which the road normally subjected.

In Fig. 2, a u'iodilied form of plate is illustrated in which the actual tread. surface is formed by the tops of a series of U-shaped projections 18 pressed out of the metal of the plate. The ends of these projections are open, as indicated at 19, so that the plastic or semi-fluid mixture of the surfacing composition, Whether the bitumen or concrete, may flow through and beneath the plate to fill the space beneath. This plate also is provided with the flanges 14 at the edges of the openings 15.

In laying this plate or the plate illustrated in Fig. 1, the procedure may be varied from that described in connection with the latter by first placing on the foundation a layer of bitumen or concrete, and thereafter laying the tread plates in position before the initial layer has hardened. .Following the placing of the plates a snfiicient additionalsurfacin g material is poured over and around the plates to bring the surface there-of to the tops of the tread projections 18. Obviously the tread plates may take mnnerous'other forms with out departure from the invention.

In laying the plates on wooden structures such as bridges or runways having interstices through which the bitumen or concrete surfacing material may flow, I may provide with each plate a suitably formed shallow tray 20 to be placed beneath the tread plate, as shown in Figs. 3 and 4. This tray receives the bitumen or other surfacing compound and retains itbeneath the plates, thereby preventing displacement or leakage through the interstices of the wooden foundation structure beneath. The plate shown in Fig. 3 is somewhat similar to that illustrated in Fig. 2 but has a different arrangement of pressedup substantially U- shaped tread'elements 21. It will be noted that in this case also the flanges 22 at the edges of the plates pass down and enclose the trays 20 so that a substantially enclosed space is formed beneath the plate which is filled with the road surfacing material and retained by side flanges of the tray and the flanges 22 of the plates,

Fig. 4 illustrates the manner in which the reinforcing plates are substantially completely embedded in the road-surfacing material while leaving the tops of'the 'upturned'flanges or pressed-up portions exposed to constitute a tread'for traffic, as previously set forth.

, VVhileI have described for the purpose of illustrating the invention anumber of em bodiments which the invention may take, it

7 Willbeunderstood that the invention is not limited to'the forms herein illustrated. Also, the hereln described metal treadand relnforcmg members lend themselves particularly well to the manufacture of preformed bituminous slabs including the tread elements which are embedded in the bltuminous composition.

These-slabs may be shipped and laid in position, and thejoints sealed by suitable means. such for example-as by heating the edges of the slabs so that they adhere together. i I claim:

.1. A tread for surfaced roads and pavements comprising a plurality of metal plates arranged. end to end and en'ibedded in the road surfacing composition, each of said plates comprising a plurality of integral upstanding elements whose upper edges lie at the surface of the road to form the tread proper.

2. A tread for surfaced roads and pavomcnts comprising a plurality of metal plates arranged end to end and embedded in the road surfacing composition, each of said plates comprising a plurality of integral upstanding elements whose upper edges lie at the surface of the road to form the tread proper, and each of said plates having at its edges depending flanges enclosing a space beneath the individual plates in which the material of the road surfacing compound is retained by said depending flanges.

S. A tread for surfaced roads and pavements comprising a plurality of metal plates arranged end to end and embedded in the road surfacing COJIIPOSli'iOl], each of said plates having at its outer edges depending flanges and having also apertures permitting passage of the road composition to the space heneath the plate. and integral upstanding elements on said plates, the top of which lie at the surface of the road to form the wearing surface of said tread.

a. A tread for surfaced roads and pa vements comprising a. plurality of plates laid end to end and embedded in the composition of the road surface, each of the said plates having openings through which the surfacing composition may flow, means on the plates for preventing displacement of the road composition from beneath the plates. and integral upstanding elements on said plates, the tops of which lie in the plane of the surface of the road and constitute the wearing tread.

5. A tread for surfaced roads and pavements comprising' a. plurality of plates laid end to end and embedded in the road composition, each of said plates having depending flanges at its edges and. apertures through which the road composition may How to the space beneath the plates. integral upstanding elements on the plate, the tops of which lie at the road surface and constitute a. wearing tread, and elen'ients covering substantially the same area as the individual pl ates and located beneath the plates and inside the said depending flanges thereby to assist in retaining the road surfacing composition in the space beneath the plates. 2

G. A tread for surfaced roads and pavements comprising a plurality of plates laid end to end and embedded in the road composition, said plates having integral upstanding elements the tops of which lie at the road surface and constitute a weaving tread. and trays underlyingthe individual plates and the said composition and functioning to retain the latter in position.

7. A bituminous road comprising a hiill) tnmen-holdingtray, bituminous material over-- lying said tray, and a perforated tread-plate overlying said bituminous material and having apertures through Which the said material extends to form With the upper surface of said plate the wearing surface of the said road.

8. A bituminous pavement for use on foundations having openings or voids, which comprises a bitumen-retaining tray to be laid upon the foundation in a position overlying the said openings, and a bituminous composition overlying the tray and prevented thereby from entering said openings.

THOMAS J. BARRETT. 

